Indigoid dyestuff



. Patented {Oct 13, 1 i,

ing 4:.6 dichloro- 3 hydroxy -thionaphthene UNITED mm;

orrlcsj v WILHELM BAUER AND nnnwre zEH, or nnvEi xUsEN-oN-rrHn-nnmn GERMAN As SIGNORS T'O GENERAL ANILINE wonxs, me, or NEW YORK, 1\T. Y., A CORPORATION or DELAWARE mnroorn nvnstrnrn No Drawing. Application filed .Tulyi7, 1930, Serial ms. 466,340, anrlin Germany .Tu1y.29,1 929 The present invention relates to an indigoid dyestuff, more particularly it relate to a dyestufl of the formula: 1 v p The new dyestufi' is obtainableby condenswith a reactive alpha-derivative of 3 -hyjdroxy-thionaphthene orby condens ng a reactive alpha-derivative of 4.6-dichloro-3- hydroxy thi onaphthene with 3 hydroxy I thionaphthene, as is more fully described 1n the example.

The dyestuff thus obtainable, 'the asymmetrical 4:.6-dichl0robis-thionaphthene indigo, is a pink crystalline powder, yielding a' yellow vat from-which textile fibers, after ample:

oxidation, are dyedclear andpowerful ruby r v dlflieultly soluble 1n sulfuric acld with a green shades of excellent fastne'ss to chlorine and light. Furthermore, the dyestuff" is well suitable for calico printing on account of the ease with which it can be fixed on the fiber.

The invention is illustrated by the ex- .Emample: 282 parts by weight of the 2- (para-dimethylami'no)ranile of 2.3-diketodihydrothionaphthene (obtainable by the action of nitroso-dimethylaniline on an alkaline solution of 3-hydroxy thionaphthene) and'219 parts by weightof 4.6-d-ichloro-3- parts by weight. of glacial acetic acid, while tures.

action of nitrosodimethylaniline on an alkaline solution I of, 4.6 dichloro-3-hydroxythionaphthene) and 150 parts by weight of 7 3-hydroxy-thionaphthene in glacial acetic acid. The 4L6-dichlor0-3hydroxy-thionaphthem is obtainable, for example,'by the action of aluminium chlorideuponthe chloride of the 3.5-dichlorophenyl-Lthioglycolic acid. o

The new dyestufi" is alsosuitable for preparing a leuco-sulfuric acid ester thereof.

'Weclaimr .7 5

As a new indigoid dyest-ufi the asymmetrical 4.6-dichloro-bis-thionaphthene indigo of,

the-formula U V a said dyestufi' being a pink v crystalline "sub.

stance, scarcely soluble in organic solvents,

coloration, yielding a'yellow Vat from which 7 textile fibers after oxidation are dyed clear powerful ruby shades of excellent fastness properties. I

In testimony. whereof, we afiix' our signa- JWILHELM BAUER.

'LUDWIG ZEH.

. rhydroxy-thionaphthene are heated in 4000 stirring until the separation of the'dyestufi V is complete. The dyestuff is sucked ofl', Y

washed with water and dried. It is a pink 7 colored crystalline powder, which is scarcely soluble inorganic solvents and which dis- I solves diiiicultly in sulfuric acid with a green coloration. It yields a yellow vatwith alkaline hydrosulfit'e, from ..which textile fibers are dyed clear ruby shades of excellent fastness properties, especially to light. a

The same dyestulf is obtainable by heating 351 parts by weight of the 2- (para-dimethyL I amino-)-anile of41.6-dichloro-2.3-diket0-di hydrothionaphthene (obtainable bv the 

